Honeywell RTH8500 Series User manual

Operating
Manual
RTH8500
Touchscreen Programmable Thermostat

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or call Honeywell Customer Care toll-free at 1-800-468-1502
BE CAREFUL! Never use sharp instruments, such as a pencil
or pen, to press touchscreen keys. To prevent damage to the
thermostat, always press keys with your fingertip.
® U.S. Registered Trademark.
US Patent No. 6,595,430 and other patents pending.
Copyright © 2006 Honeywell International Inc.
All rights reserved.

RTH8500
1
About your new thermostat
Thermostat features ..........................2
Programming at a glance..................3
Quick reference to controls ..............4
Quick reference to status display ....5
Programming & Operation
Clock setting ......................................6
Fan setting ........................................7
System setting....................................8
Using program schedules ................9
Program schedule overrides ..........12
Vacation hold ..................................14
Special features ..............................15
Screen cleaning ..............................16
Furnace filter reminder ....................17
Appendices
Battery replacement ........................18
In case of difficulty ..........................19
Limited warranty ..............................21
Table of contents
This thermostat is ready to go!
Your new thermostat is pre-
programmed and ready to go.
See page 3 to check settings.
CAUTION: EQUIPMENT DAMAGE
HAZARD. To prevent possible
compressor damage, do not operate
cooling system when outdoor
temperature is below 50°F (10°C).

Operating Manual
2
About your new thermostat
Congratulations! You’ve just purchased the world’s most advanced, easy-
to-use thermostat. It has been designed to give you many years of reliable
service and touchscreen climate control.
Features
• 7-day program schedules maximize comfort and economy.
• Armchair programming: Just pull thermostat from the wall to set schedules.
• EnergyStar®compliant to greatly reduce your heating/cooling expenses.
• One-touch temp control overrides program schedule at any time.
• Precise comfort control keeps temperature within 1°F of the level you set.
• Change/check reminders let you know when to replace filters and batteries.
• Large touchscreen display with backlight is easy to read — even in the dark.

RTH8500
3
This thermostat is ready to go!
Your new thermostat is pre-programmed and ready to go. All you have to
do is set the time and day. Then check the settings below and change if
needed:
1Set clock......................................................................................See page 6
2Select fan setting: Preset to Auto ........................To change, see page 7
3Select system setting: Preset to Heat ..................To change, see page 8
4Program schedules: Preset to energy-saving levels
while you’re at work or asleep (assumes you
wake at 6 am, leave at 8 am, return at 6 pm
and go to bed at 10 pm) ..................................To change, see pages 10-13
ONE-TOUCH TEMP CONTROL: You can override the program schedule at any time,
and manually adjust the temperature (see pages 12-14).

MON TUE WED THU FRI SAT SUN
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
OK TO PICK MULTIPLE DAYS
Inside
70 Set To
Following
Schedule
70
AM
6:01
Operating Manual
4
Quick reference to controls
Press day(s) to set program schedule (see page 11)
Press to select fan
operation (see page 7)
Press to adjust
temperature settings
(see pages 11-14)
Press to set program
schedule (see page 11)
Press to override
program schedule
(see pages 12-14)
Press to set clock
(see page 6)
Press to lock keypad for 30
seconds to clean screen
(see page 16).
Press to select system
type (see page 8)
Press for more options
(select models only)

WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To
Following
Schedule
Recovery
70
AM
6:01
RTH8500
5
Quick reference to status display
Current inside temperature Current day of week Temperature setting
System setting
Fan setting
Smart Response®
Technology in effect
(see page 15)
Program schedule on
(does not display
when off)
Current time Other display messages:
•Cool On: Cooling system is activated
•Heat On: Heating system is activated
•Aux Heat On: Auxiliary heating system is activated
(heat pump systems only)

Operating Manual
6
Clock setting
To set the current time display,
press clock, then press or
to adjust the time. Press and
hold or to advance the time
more quickly.
Press DDOONNEEto save & exit (or press
CCAANNCCEELLto exit without changing
the time).
Note: The real-time clock should never
require adjustment since it automatically
updates for daylight savings time, and
stores all date/time information.
Note: To change the current week day
display, see System Setup in your
Installation Guide.
Press CCLLOOCCKK
Adjust time, then press DDOONNEE
SCHED HOLD CLOCK SCREEN MORE
AM
6:01
DONE CANCEL
AM
6:02

RTH8500
7
Fan setting
Press FFAANNto select fan operation:
•On: Fan is always on.
•Auto: Fan runs only when the heating
or cooling system is on.
WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To
Following
Schedule
70
AM
6:01
Press FFAANN

Operating Manual
8
System setting
Press the SSYYSSTTEEMMbutton to select:
•Heat: Thermostat controls only the
heating system.
•Cool: Thermostat controls only the
cooling system.
•Auto: Thermostat automatically
selects heating or cooling depending
on the indoor temperature.
•Off: Heating and cooling systems
are off.
•Em Heat (only for heat pumps with
auxiliary heat): Thermostat controls
Emergency and Auxiliary Heat.
Compressor is locked out.
WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To
Following
Schedule
70
AM
6:01
Note: The Auto and Em Heat
system settings may not appear,
depending on how your
thermostat was installed.

RTH8500
9
WAKE
6:00 am
70 °
LEAVE
8:00 am
62 °
RETURN
6:00 pm
70 °
SLEEP
10:00 pm
62 °
Set to the time you awaken and the temperature you
want during the morning, until you leave for the day.
Set to the time you leave home and the temperature you
want while you are away (usually an energy-saving
level).
Set to the time you return home and the temperature
you want during the evening, until bedtime.
Set to the time you go to bed and the temperature you
want overnight (usually an energy-saving level).
Save money by setting program schedules
It’s easy to program your system for maximum energy savings. You can
program four time periods each day, with different settings for weekdays
and weekends.

Operating Manual
10
EnergyStar®settings for maximum cost savings
This thermostat is pre-set to use EnergyStar®program settings. We recom-
mend these settings, since they can reduce your heating/cooling expenses by
as much as 33%. (See next page to adjust times and temperatures of each
time period.)
70
°
78
°
70
°
78
°
62
°
85
°
62
°
85
°
70
°
78
°
70
°
78
°
62
°
82
°
62
°
82
°
Heat (Mon-Fri) Cool (Mon-Fri) Heat (Sat-Sun) Cool (Sat-Sun)
Wake
(6:00 am)
Leave
(8:00 am)
Return
(6:00 pm)
Sleep
(10:00 pm)
[Or cancel period]
[Or cancel period]
[Or cancel period]
[Or cancel period]

RTH8500
11
To adjust program schedules
1 Press SSCCHHEEDD, then EEDDIITT.
2 Press day buttons (MMOONN--SSUUNN) to select
day(s).
3 Press or to set Wake time for
selected day(s).
4 Press or to set Heat and Cool
temperature for this time period.
5 Press other time periods (LLEEAAVVEE, RREETTUURRNN,
SSLLEEEEPP) to set time and temperatures
for each.
6 Press DDOONNEEto save & exit (or press
CCAANNCCEELLto exit without saving changes).
Note: You can press CCAANNCCEELLPPEERRIIOODDto eliminate any
unwanted time period.
Press SSCCHHEEDD
SCHED HOLD CLOCK SCREEN MORE
Press EEDDIITT
Select day(s)
Set time for program
period start
Set heat/cool levels
EDITDONE WAKE LEAVE RETURN SLEEP CANCEL
MON TUE WED THU FRI SAT SUN
HEAT
COOL
AUTO
FAN
OK TO PICK MULTIPLE DAYS
70
78
AM
6:00
DONE WAKE LEAVE RETURN SLEEP CANCEL
CANCEL
PERIOD

WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE CANCEL
AUTO
FAN
Inside
70 Set To
Hold Temperature
Until
73
AM
8:00
Operating Manual
12
Program schedule override (temporary)
Press or to immediately adjust the
temperature. This will temporarily over-
ride the temperature setting for the
current time period.
The new temperature will be maintained
until the time you set. When the timer
expires, the program schedule will
resume and set the temperature to the
level you’ve programmed for the current
time period.
To cancel the temporary setting at any
time, press CCAANNCCEELL(or SSCCHHEEDD). The program
schedule will resume.
Press CCAANNCCEELL(or SSCCHHEEDD) to
resume program schedule
Press to set timer
Adjust temperature
Heat On

RTH8500
13
Program schedule override (permanent)
Press HHOOLLDDto permanently adjust the
temperature. This will turn off the
program schedule.
Whatever temperature you set will be
maintained 24 hours a day, until you
manually change it, or press CCAANNCCEELL(or
SSCCHHEEDD) to cancel “Hold” and resume the
program schedule.
WED
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE CANCEL
AUTO
FAN
Inside
70 Set To
Permanent
Hold
73
AM
8:00
Press CCAANNCCEELL(or SSCCHHEEDD) to
resume program schedule
Press HHOOLLDDAdjust temperature
Heat On

Operating Manual
14
Vacation hold
This feature can suspend the program
schedule for extended periods of time.
Press or to set the temperature you
want, then press or to set the time
of day you want the schedule to resume
when you return. Press HHOOLLDDtwice, then
press or to select the number of
days.
Whatever temperature you set will be
maintained 24 hours a day for the num-
ber of days you select. After this number
of days have elapsed, the previously
programmed schedule will resume at the
time you set.
If you return earlier than expected, press
CCAANNCCEELL(or SSCCHHEEDD) to cancel “Hold” and
resume the program schedule.
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE CANCEL
AUTO
FAN
Inside
70 Set To
Hold Temperature
Until
55
6:00pm
1Set temperature
2Press to set time for
schedule to resume
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE CANCEL
Hold Temperature
Until
14
3Press HHOOLLDDtwice
4Press to select number of days
DAYS

RTH8500
15
Special features
Smart Response®Technology: This feature allows the thermostat to
“learn” how long the furnace and air conditioner take to reach programmed
temperature settings, so the temperature is reached at the time you set.
For example: Set the Wake time to 6 am, and the temperature to 70°. The
heat will come on before6 am, so the temperature is 70° by the time you
wake at 6. The message “Recovery” is displayed when the system is
activated before a scheduled time period.
Compressor Protection: This feature forces the compressor to wait a few
minutes before restarting, to prevent equipment damage. During the wait
time, the message “Wait” is displayed on screen.
Auto Changeover: This feature is used in climates where both air condi-
tioning and heating are used on the same day. When the system is set to
Auto, the thermostat automatically selects heating or cooling depending on
the indoor temperature. Heat and cool settings must be at least 3 degrees
apart. The thermostat will automatically adjust settings to maintain this
3-degree separation.
CAUTION: To avoid possible compressor damage, do not use Auto Changeover if the
outside temperature drops below 50°F (10°C).

Operating Manual
16
Screen cleaning
Press SSCCRREEEENNto lock the screen for clean-
ing. The screen will remain locked for 30
seconds so you can clean the screen
without changing any settings.
After 30 seconds, press DDOONNEEto resume
normal operation, or press SSCCRREEEENNagain if
you require more time for cleaning.
Note: Do not spray any liquid directly on the
thermostat. Spray liquids onto a cloth, then use the
damp cloth to clean the screen. Use water or
household glass cleaner. Avoid abrasive cleansers.
30 OKAY TO
CLEAN
SCREEN
SCHED HOLD CLOCK SCREEN MORE
PM
6:00
Press SSCCRREEEENN
Screen lock timer (30 seconds)

RTH8500
17
Furnace filter reminder
If activated during installation, the
furnace filter reminder alerts you when it
is time to replace your filter.
Press RREESSEETTafter changing the filter, to
restart the timer.
To change the reminder interval:
1 Press MMOORREE, then EEDDIITT.
2 Press or to select the desired
interval, then press DDOONNEE.
3 Press RREESSEETT.
4 Press DDOONNEEto save and exit.
HEAT
SYSTEM
SCHED HOLD CLOCK SCREEN MORE
AUTO
FAN
Inside
70 Set To55
6:00pm
CHANGE FILTER
RESET
Press RREESSEETTafter changing filter
DONE
Filter
Days
60
Press MMOORREEto change reminder interval

Operating Manual
18
Battery replacement
Batteries are optional (to provide backup
power) if your thermostat was wired to
run on AC power when installed.
Install fresh batteries immediately when
the LLOOBBAATTTTwarning begins flashing. The
warning flashes about 30 days before
batteries are depleted.
Even if the warning does not appear, you
should replace batteries once a year, or
before leaving home for more than a
month.
Insert 3 fresh AAA alkaline batteries
Grasp thermostat and pull
to remove from wallplate